Retractable electric range apparatus

ABSTRACT

A retractable electric range apparatus with a frame mounted within an opening in the upper surface of an electric stove. At least three vessel supports extend upwardly from the frame and have their upper ends terminating in a common horizontal plane to support a cooking vessel thereon. At least three vertical and circumferentially spaced plungers are slidably received within sleeves which protrude through the frame, each plunger having an upper end which is slotted and a lower end with a cam follower thereon. A substantially horizontal and rotatable disc is resiliently supported beneath the frame, the disc having a peripheral rim extending perpendicularly above the disc. A cam is formed on the rim of the disc by period projections and depressions of the rim upon which the followers of the plungers are engaged. A heating element is supported above and substantially parallel to the frame. A plurality of radial support arms are disposed beneath the heating element for supporting the same, while engaging the upper ends of the plungers. An electrically responsive device is provided to impart rotation to the cam so that when the heating element is activated it is raised into engagement with the bottom of a cooking vessel and lowered from the vessel when the heating element is deactivated.

United States Patent [191 Sego, Jr. et al.

[ RETRACTABLE ELECTRIC RANGE APPARATUS [75] Inventors: James T. Sego,Jr., Tahlequah;

Arless B. Noble, Norman, both of Okla.

[73] Assignee: Instant Off Incorporated,

Tahlequah, Okla.

[22] Filed: Nov. 25, 1974 [21] Appl. No.: 526,699

3,440,406 4/1969 Sego, .lr. 3,578,951 4/1971 lngrao 219/444 3,761,6809/1973 Ingrao 219/456 Primary Examinervolodymyr Y. Mayewsky Attorney,Agent, or FirmWilliam S. Dorman Aug. 5, 1975 [57] ABSTRACT A retractableelectric range apparatus with a frame mounted within an opening in theupper surface of an electric stove. At least three vessel supportsextend upwardly from the frame and have their upper ends terminating ina common horizontal plane to support a cooking vessel thereon. At leastthree vertical and circumferentially spaced plungers are slidablyreceived within sleeves which protrude through the frame, each plungerhaving an upper end which is slotted and a lower end with a cam followerthereon. A substantially horizontal and rotatable disc is resilientlysupported beneath the frame, the disc having a peripheral rim extendingperpendicularly above the disc. A cam is formed on the rim of the discby period projections and depressions of the rim upon which thefollowers of the plungers are engaged. A heating element is supportedabove and substantially parallel to the frame. A plurality of radialsupport arms are disposed beneath the heating element for supporting thesame, while engaging the upper ends of the plungers. An electricallyresponsive device is provided to impart rotation to the cam so that whenthe heating element is activated it is raised into engagement with thebottom of a cooking vessel and lowered from the vessel when the heatingelement is deactivated.

8 Claims, 10 Drawing Figures PATENTEU M13 5 SHEET PATENTED AUG 5 I975SHEET SHEET PATENTED AUG 5l975 RETRACTABLE ELECTRIC RANGE APPARATUSBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to improvements in electrical heating elements for cook stoves,and more particularly I to a reciprocal heating element whichautomatically retracts away from a cooking vessel upon interruption ofan electrical current thereto.

2. Description of the Prior Art Methods for removal of electricalheating elements from contact with the bottom of cooking vessels havebeen shown in prior art. Of particular significance is Fernicola US.Pat. No. 2,810,058 (1957), wherein a single rigid support is used toraise and lower an electric heating element. Such single support isparticularly disadvantageous if the heating element is to be in intimatecontact with the bottom of a cooking vessel, due to the lack ofstability of a single point support. This disadvantage was partiallyovercome by the Applicants prior patent, Sego US. Pat. No. 3,440,406(1969), wherein yieldable means for the support of the electricalheating element was provided. However, a further disadvantage as shownin the prior art was the necessity for a substantial clearance beneaththe existing stove top to accommodate the retraction mechanisms. Thepresent invention overcomes all of these disadvantages by providingyieldable support means for the electrical heating element therebyinsuring intimate contact with a cooking vessel. Additionally, at leastthree point support is provided for the heating element, therebyincreasing the stability of the heating element. Further, spacerequirements are reduced by use of a circumferential cam about theperpendicular rim of a horizontal disc.

SUMMARY OF THE INVENTION This invention relates to the improvement of are tractable electric range apparatus wherein yieldable support meansare provided for the heating element; increased stability of the heatingelement is accomplished by use of at least three cam followers for theretraction means; and, the reduction of space requirements beneath thesurface ofa stove top is achieved by use of a cam circumferential aboutthe upwardly extending perimeter of a horizontal disc.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a plan view illustrating a retractable electric rangeapparatus incorporating the present invention;

FIG. 2 is a view along line 22 in FIG. 1;

FIG. 3 is a view similar to FIG. 1, with certain elements removed forclarity, showing details of the rotation means of this invention;

FIG. 4 is a view along line 44 of FIG. 3; FIG. 5A is a modification ofthe pawl shown in FIG.

FIG. 5B shows the reverse side of the pawl shown in FIG. 4;

FIG. 6 is a top view of a horizontal disc and segmented circuit boardemployed in the apparatus of the present invention;

FIG. 7 is a view along line 77 in FIG. 6;

FIG. 8 is a top view illustrating a second embodiment of this inventionutilizing a different rotative means; and

FIG. 9 is a plan view along line 99 of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2 indetail, there is shown an upper surface 10 of an electric stove of thetype having a range opening 11 in the upper surface thereof. Aretractable electric range apparatus 12 is supported within the openingof the stove by a frame means 14, later to be described in detail. Atrim ring 15 is inserted into the opening 11 of the stove top 10 forappearance and to receive a base means 16 therein. The base means 16provides support for a drip pan 17 thereabove. At least three vesselsupports 18 are fixed to the drip pan 17, the vessel supports 18projecting upwardly therefrom and having their upper ends 19 terminatingin a common horizontal plane for supporting a cooking vessel (not shown)thereon.

A plurality of at least three sleeves 34 protrude through the base means16. The sleeves 34 are substantially vertical and circumferentiallyspaced about the base means 16. A plunger 36 is slidably received withineach of the sleeves 34. The plunger 36 has a slotted upper end 38 and alower end with a cam follower 40 thereon.

A substantially horizontal frame 26 is positioned beneath the base means16. An assembly screw 28 is affixed perpendicularly above and to theframe 26. A center nut 30 is threadedly engaged upon the assembly screw28. As shown in FIG. 2, the upper end of the cen ter nut 30 terminatesin the common horizontal plane with the upper ends 19 of the vesselsupports 18, thereby providing additional support for a vessel at thecenter thereof. The base means 16 is received upon the assembly screw 28and held against the frame 26 by the center nut 30. An elongated tube 42is connected below and perpendicular to the frame 26. The upper end ofthe tube 42 receives the assembly screw 28 therein. A bearing 44 isfixedly secured within the lower end of the tube 42. A retainer 46 isvertically reciprocal within the tube 42. A spring 48 is containedwithin the tube 42 and separates the retainer 46 from the bearing 44. Athreaded tension adjuster 50 passes downward through the retainer 46 andspring 48. A threaded bushing 52 projects upwardly through the bearing44, and receives the lower end of the threaded tension adjuster 50therein. A substantially horizontal disc 54 is engaged between thebearing 44 and the bushing 52. A peripheral rim 56 extends substantiallyperpendicular above the disc 54. A cam 58 is formed on the rim 56 of thedisc 54 by periodic projections 60 and depressions 62 of the rim 56. Thecam followers 40 of the plungers 36 are engaged upon the cam 58.

A heating element 20 is disposed substantially parallel to the framemeans 14 and vertically reciprocal thereabove. A plurality of radialsupport arms 22 beneath the heating element 20 support the same and arepreferably connected thereto by welding or the like. The radial supportarms 22 engage the slotted upper ends 38 of the plungers 36 therebytransmitting any elevational change experienced by rotation of the cam58 to the radial support arms 22 which, in turn, vary the elevation ofthe heating element 20.

Referring now to FIGS. 3 and 4 in detail, a means for imparting rotationto the disc 54 and the cam 58 is shown. The rotational means iscomprised of a cylinder 64 rotatably received on the tube 42 of theframe 26.

The cylinder 64 has an upper portion 66 and a lower portion 68 separatedfrom the upper portion by a peripheral flange or ridge 70, having a hole72 therein. A first spring 74 is wound about the upper portion of thecylinder 64 with one end 76 thereof being affixed to the horizontalframe 26 and the other end 78 thereof being received within the hole 72in the ridge 70. This first spring imparts a downward thrust upon theridge 70, thereby keeping the cylinder 64 positioned downward.

A second spring 80 is wound about the lower portion 68 of the cylinder64. The second spring 80 has an upper end 82 and a lower end 84 thereon.The upper end 82 of the second spring 80 extends perpendicularly fromthe cylinder 64. A rotatable arm 86 is mounted on the lower portion 68of the cylinder 64 and extends perpendicularly from the cylinder. Thearm 86 has a hole 88 therein, into which the lower end 84 of the secondspring 80 is received. A finger 90 protrudes upwardly from the arm 86.The finger 90 has a hole 92 in its uppermost end. A dashpot 94 isaffixed to and beneath the frame 26. A rod 96 projects outwardly fromthe dashpot 94, and is received within the hole 92 of the finger 90. Apawl 98 is attached to the outer end of the arm 86. A movable guide shoe112 is attached to the pawl 98, the guide shoe 112 being slidableagainst the disc 54. A spring 108 disposed about a fulcrum 99spring-loads the guide shoe 112 into contact with the disc 54.

A plunger type solenoid 100 is mounted beneath the frame 26. A plunger102 of the solenoid 100 engages the upper end 82 of the second spring 80to rotate the cylinder 64 and cam 86 when the solenoid is energized. Thedashpot 94 serves to dampen the action of the solenoid 100.

An electrical contact means 104 is provided to activate the solenoid100, and is comprised of a nonconductive circuit board 114 attached tothe disc 54. The circuit board 114 has a plurality of segments 116attached thereto. The segments 116 are electrically conductive andspaced in relationship corresponding to the projections 60 anddepressions 62 of the cam 58. A set of brushes 118 contact the segments116 of the circuit board 114. The brushes 118 are connected to anactivation means (not shown) for the heating element 20.

A plurality of ratchet teeth 106 are provided on the disc 54. Theratchet teeth 106 are circumferentially spaced and numerically relatedto the number of projections 60 and depressions 62 of the cam 58, andare engagable by the pawl 98.

P16. A illustrates a variation of the pawl 98, wherein a movable tooth110 is pivotally mounted on a pin 109 connected to the arm 86. FIG. 5Billustrates the spring-loading of the movable tooth 110 by means of aspring 111 which is received on the pin 109. One end of the spring 111engages a second fixed pin 113 on the arm 86 and the other end of thespring engages a projection 115 on the tooth 110.

The spatial relationship of the segments 116 of the circuit board 114 tothe ratchet teeth 106 is shown in FIG. 6. A separate tooth 106 andassociated segment 116 are provided for each projection 60 anddepression 62 of the cam 58.

FIGS. 8 and 9 illustrate a second embodiment of this invention. Theelectrical contact means 104 has been heretofore described. Therotational means illustrated is comprised of an electric motor 120having a shaft 122 upon which a gear 124 is affixed. A ring gear 126 isattached to the disc 54 and engages the gear 124 thereon. Of course, inthe second embodiment shown in FIGS. 8 and 9, the solenoid, pawl,ratchet teeth, dashpot, first and second springs and associatedstructure are eliminated.

The cam follower 40 of the plunger 36 is comprised of a concave wheel 41located within a slot 39 and affixed to the plunger 36 by an axle 43.The wheel 41 is received upon the rim 56 of the disc 54, and rotatesabout the axle 43 as the cam 58 is rotated.

Operation Electrical power is supplied to the apparatus through aconnector 24 and someactivation means (not shown) such as a switch orswitches. The arrangement of the activation means (or switches) would besuch that power would be supplied to certain of the brushes 118 so thatthe solenoid (or motor would be actuated momentarily to move the heatingelement upwardly in the on position and downwardly in the off positionof the switch, as will appear hereinafter. For example, in the offposition, the plungers 36 would be substantially at their lowermostposition, the cam followers engaging the cam 58 within the depressions62. Upon activation of the heating element 20 (turning to the onposition), the solenoid 100 would also be activated, thereby causing thepawl 98 of the rotatable arm 86 to engage a ratchet tooth 106 thereon.Movement of the plunger 102 of the solenoid 100 would impart arotational motion to the arm 86 about cylinder 64 through the secondspring 80. Possible abrupt movement ofthe arm 86 would be dampened bythe dashpot 94. The plungers 36 with their associated cam followers 40would be raised upwardly as the disc 54 and its peripheral cam 58rotate. The upward elevational change of the plunger 36 would betransmitted to the radial support arms 22 which are engaged in theslotted upper ends 38 of the plungers 36. The heating element 20 beingsupported upon the radial support arms 22 would reflect the elevationalchange associated with the cam 58.

The spring 48 would be initially adjusted by the tension adjuster 50when no cooking vessel was on the apparatus, and when the heatingelement 20 was at its maximum upward elevation so that the top surfaceof the heating element would be in a horizontal plane slightly above thecommon horizontal'plane in which the upper ends 19 of the vesselsupports 18 and the center nut 30'reside. Upon placement of a cookingvessel (not shown) upon the top surface of the heating element 20, theheating element would be displaced slightly downward, with acorresponding downward displacement of the plungers 36 being transmittedto the spring 48. The spring 48 being slightly in compression therebywould exert an opposite force tending to cause the heating element 20 toreturn to its no load position. This would cause the heating element 20to intimately contact the bottom of a cooking vessel.

The solenoid 100 would be only momentarily activated as power wasapplied through one set of brushes 118 and theconductive segments 116corresponding to the depressions 62, or the lowered position of theheating element; rotation of the disc 54.would move the segments 116beyond the actuated brushes and the solenoid would be deenergized.

Lowering of the heating element would be accomplished opposite to themanner described above. That is, turning the switch or activation means(not shown) to the of position would supply power to the other set ofbrushes which are now in contact with the segments 116 corresponding tothe projections 60 (or raised position of the heating element). Thesolenoid 100 would again be activated momentarily to rotate the disc 54until the other set of brushes are beyond the high segments 116 at whichtime the solenoid 100 would be deenergized.

Rotation using the second embodiment herein would be achieved by themomentary activation of the contact means 104 and the electric motor120, power being interrupted as the brushes 118 pass beyond the lowsegments 116 as described above. Lowering would be accomplished also asdescribed above.

What is claimed is:

l. A retractable electric range apparatus for an electric stove of thetype having a range opening in the upper surface thereof, comprising aframe means mounted within said opening in fixed position relative tosaid stove, at least three vessel support means extending upwardly fromsaid frame means and terminating at their upper ends in a commonhorizontal plane for supporting a vessel thereon, at least threesubstantially vertical and circumferentially spaced sleeves protrudingthrough said frame means, a plunger slidably received within each ofsaid sleeves, each plunger having an upper end extending above saidframe means and having a lower end with a cam follower thereon, asubstantially horizontal and rotatable disc resiliently supported frombeneath said frame means, said disc having a peripheral rim extendingsubstantially perpendicular above said disc, a cam formed on said rim ofsaid disc by periodic projections and depressions of said rim, saidfollowers by said plungers engaging said cam, an electric heatingelement substantially parallel to said frame means and locatedthereabove, a plurality of radial support arms beneath said heatingelement and supporting the same, said radial support arms engaging theupper ends of said plungers, and rotational means responsive to theactivation of said heating element for causing rotation of said cam toraise said heating element into engagement with said vessel when saidheating element is activated and for causing rotation of said cam tolower said heating element away from said vessel when said heatingelement is deactivated.

2. A retractable electric range apparatus as set forth in claim 1wherein said frame means comprises a substantially horizontal frame, anassembly screw perpendicularly affixed above said frame, a center nutthreadedly engaged upon said assembly screw, a base means received uponsaid assembly screw and affixed thereto by said center nut, said basemeans engaging said stove in the region of said opening, wherein saidspaced sleeves protrude through said base means, wherein each plunger isslotted at its upper end, wherein said disc is resiliently supportedfrom said frame means by an elongated tube connected below andperpendicular to said frame, the upper end of said tube receiving saidassembly screw therein, a bearing within the lowermost end of said tube,a retainer above said bearing, said retainer being vertically reciprocalwithin said tube, a spring within said tube between said retainer andsaid bearing, a threaded tension adjuster passing downward through saidbearing and being threadedly engaged 6 upon said tension adjuster, saiddisc being engaged between said bearing and said bushing, and whereinsaid radial support arms engage said slotted upper ends of saidplungers.

3. A retractable electric range apparatus as set forth in claim 2wherein the upper end of said center nut terminates in said commonhorizontal plane and constitutes one of the vessel support means.

4. A retractable electric range apparatus as set forth in claim 2wherein said rotational means is comprised of a cylinder concentricabout said tube of said frame, said cylinder having an upper and a lowerportion thereof, a ridge about said cylinder separating said upper andsaid lower portions, said ridge having a hole therein, a first springwound about said upper portion of said cylinder, one end of said firstspring being affixed to said horizontal frame and said other end of saidfirst spring being located within said hole in said ridge on saidcylinder, a second spring wound about said lower portion of saidcylinder, said second spring having an upper and lower end thereof, saidupper end of said second spring extending perpendicularly from saidcylinder, a rotatable arm mounted on said lower portion of saidcylinder, said arm extending perpendicularly from said cylinder, saidarm also having a hole therein receiving said lower end of said secondspring therein, a finger upwardly protruding from said arm, said fingera hole ahole in its uppermost end, a dashpot affixed beneath said frame,said dashpot having a rod outwardly projecting therefrom, said rod beingreceived within said hole of said finger, a pawl attached to an outerend of said arm, a plunger type solenoid mounted beneath said frame, aplunger of said solenoid engaging said upper end of said spring,electrical contact means to activate said solenoid, a plurality ofratchet teeth on said horizontal disc, said ratchet teeth beingcircumferentially spaced and being numerically related to the number ofthe projections and depressions of said cam, said ratchet teeth beingengagable by said pawls.

5. A retractable electric range apparatus as set forth in claim 4wherein each pawl has a spring-loaded tooth thereon, said pawl alsohaving a movable guide shoe attached thereto and slidable against saiddisc, said ratchet teeth being engagable by said teeth of said pawls.

6. A retractable electric range apparatus as set forth in claim 4wherein said electrical contact means is comprised of a non-conductivecircuit board attached to said disc with a plurality of segmentsattached to said board, said segments of said circuit board beingelectrically conductive and being spaced in relationship to saidprojections and depressions of said cam, brushes contacting saidsegments of said circuit board, said brushes being connected to saidactivation means for said heating element.

7. A retractable electric range apparatus as set forth in claim 2wherein said rotational means is comprised of an electric motor mountedbeneath said frame, said motor having a shaft therethrough, a gearaffixed upon said shaft of said motor, a ring gear affixed upon saiddisc, said gear on said electric motor engaging said ring gear,electrical contact means to activate said electric motor.

8. A retractable electric range apparatus as set forth in claim 7wherein said electrical contact means is comprised of a non-conductivecircuit board attached to 7 8 said disc and having a plurality ofsegments attached contacting said segments of said circuit board, saidthereto, said segments of said circuit board being elecbrushes beingconnected to said activation means for trically conductive and beingspaced in relationship to said heating element. said projections anddepressions of said cam, brushes

1. A retractable electric range apparatus for an electric stove of thetype having a range opening in the upper surface thereof, comprising aframe means mounted within said opening in fixed position relative tosaid stove, at least three vessel support means extending upwardly fromsaid frame means and terminating at their upper ends in a commonhorizontal plane for supporting a vessel thereon, at least threesubstantially vertical and circumferentially spaced sleeves protrudingthrough said frame means, a plunger slidably received within each ofsaid sleeves, each plunger having an upper end extending above saidframe means and having a lower end with a cam follower thereon, asubstantially horizontal and rotatable disc resiliently supported frombeneath said frame means, said disc having a peripheral rim extendingsubstantially perpendicular above said disc, a cam formed on said rim ofsaid disc by periodic projections and depressions of said rim, saidfollowers by said plungers engaging said cam, an electric heatingelement substantially parallel to said frame means and locatedthereabove, a plurality of radial support arms beneath said heatingelement and supporting the same, said radial support arms engaging theupper ends of said plungers, and rotational means responsive to theactivation of said heating element for causing rotation of said cam toraise said heating element into engagement with said vessel when saidheating element is activated and for causing rotation of said cam tolower said heating element away from said vessel when said heatingelement is deactivated.
 2. A retractable electric range apparatus as setforth in claim 1 wherein said frame means comprises a substantiallyhorizontal frame, an assembly screw perpendicularly affixed above saidframe, a center nut threadedly engaged upon said assembly screw, a basemeans received upon said assembly screw and affixed thereto by saidcenter nut, said base means engaging said stove in the region of saidopening, wherein said spaced sleeves protrude through said base means,wherein each plunger is slotted at its upper end, wherein said disc isresiliently supported from said frame means by an elongated tubeconnected below and perpendicular to said frame, the upper end of saidtube receiving said assembly screw therein, a bearing within thelowermost end of said tube, a retainer above said bearing, said retainerbeing vertically reciprocal within said tube, a spring within said tubebetween said retainer and said bearing, a threaded tension adjusterpassing downward through said bearing and being threadedly engaged uponsaid tension adjuster, said disc being engaged between said bearing andsaid bushing, and wherein said radial support arms engage said slottedupper ends of said plungers.
 3. A retractable electric range apparatusas set forth in claim 2 wherein the upper end of said center nutterminates in said common horizontal plane and constitutes one of thevessel support means.
 4. A retractable electric range apparatus as setforth in claim 2 wherein said rotational means is comprised of acylinder concentric about said tube of said frame, said cylinder havingan upper and a lower portion thereof, a ridge about said cylinderseparating said upper and said lower portions, said ridge having a holetherein, a first spring wound about said upper portion of said cylinder,one end of said first spring being affixed to said horizontal frame andsaid other end of said first spring being located within said hole insaid ridge on said cylinder, a second spring wound about said lowerportion of said cylinder, said second spring having an upper and lowerend thereof, said upper end of said second spring extendingperpendicularly from said cylinder, a rotatable arm mounted on saidlower portion of said cylinder, said arm extending perpendicularly fromsaid cylinder, said arm also having a hole therein receiving said lowerend of said second spring therein, a finger upwardly protruding fromsaid arm, said finger a hole ahole in its uppermost end, a dashpotaffixed beneath said frame, said dashpot having a rod outwardlyprojecting therefrom, said rod being received within said hole of saidfinger, a pawl attached to an outer end of said arm, a plunger typesolenoid mounted beneath said frame, a plunger of said solenoid engagingsaid upper end of said spring, electrical contact means to activate saidsolenoid, a plurality of ratchet teeth on said horizontal disc, saidratchet teeth being circumferentially spaced and being numericallyrelated to the number of the projections and depressions of said cam,said ratchet teeth being engagable by said pawls.
 5. A retractableelectric range apparatus as set forth in claim 4 wherein each pawl has aspring-loaded tooth thereon, said pawl also having a movable guide shoeattached thereto and slidable against said disc, said ratchet teethbeing engagable by said teeth of said pawls.
 6. A retractable electricrange apparatus as set forth in claim 4 wherein said electrical contactmeans is comprised of a non-conductive circuit board attached to saiddisc with a plurality of segments attached to said board, said segmentsof said circuit board being electrically conductive and being spaced inrelationship to said projections and depressions of said cam, brushescontacting said segments of said circuit board, said brushes beingconnected to said activation means for said heating element.
 7. Aretractable electric range apparatus as set forth in claim 2 whereinsaid rotational means is comprised of an electric motor mounted beneathsaid frame, said motor having a shaft therethrough, a gear affixed uponsaid shaft of said motor, a ring gear affixed upon said disc, said gearon said electric motor engaging said ring gear, electrical contact meansto activate said electric motor.
 8. A retractable electric rangeapparatus as set forth in claim 7 wherein said electrical contact meansis comprised of a non-conductive circuit board attached to said disc andhaving a plurality of segments attached thereto, said segments of saidcircuit board being electrically conductive and being spaced inrelationship to said projections and depressions of said cam, brushescontacting said segments of said circuit board, said brushes beingconnected to said activation means for said heating element.